I started to need to cut thin sheet metal 18g to 22g for my work, but because of material warps I looked into getting a THC. But because my plasma cuts are only 5% of my business I went for the most afordable one ... Proma THC 150. I sucessfully set it up in my non-contact cnc plasma cutter. Test moves Z up and down correctly, and my table always cut well without issues prior to adding THC. What happens is when cutting and arc is on THC works up/down correctly. When arc is off and mach3 shows Z going up 15mm for safe travel torch does not go up and in the next cut it will hit material. Everything is connect to earth . Tryed lot's of things with no result. Please help ... Thanks

Thanks for the replys.I do use sheetcam and i will try that. One thing i also found out today is I'm also loosing steps in the X and Y axis when i have THC powered on. Maybe the THC is making lots of interference to the BOB. I´m using a foil shielded cable from THC to BOB and the foil is grounded. Should i add a ferrite clamp to this cable? Don't know what else to do. So frustrating.

What about the shield on the motor cables?? Only attach the shield at the controller end. Did you connect the power supply negative for the THC to the signal ground on the THC they are not the same.I assume when you say THC powered on you are cutting with the plasma also.Are you running you torch cable with the other cables??

What do you mean with the shield? All my motor cables are shielded and grounded. " only attach the shield at the controller end" , what do you mean by this? My power supply to THC is a dedicated 12v one separated from everything else connected to the 220v main. My torch cable is not running with any cables but crosses over the THC cable at one part 2 inchs apart. I will try a bigger distance.

Quick update.I changed the THC 4 wire cable to same grade as my motor cables. It is now a wire mesh insulated cable. I moved the THC cable away from torch cables to at least 2 feet. Now my Z aparently moves correctly. But... I still getting what it seems a lot of noise from the THC itself because when i do a cut and tell the machine to go back to home, there is a diference of several mm in the X and Y position , meaning lots of steps being lost or added i don't know. Any way to eliminate this noise on THC cables?

It was a guess on my part but that value has worked on the tables I built. I made it long enough to cover the random noise length.The delay needs to be longer then a noise spike, a switch change will be on longer then that delay or it the switch bounces the delay covers that too.

I would like to bring good news but when i was trying diferent settings for debounce interval my mach3 stopped working and will not unlock. I keep reseting and always get the ''error on reset '' window for inputs. I can't unlock it and even removed the serial cable from PC and the damn thing is still detecting a error on inputs and reset limits . What's going on? I've changed pin numbers and everything. Anyone else had this problem before. Now i can't even use the plasma table for my normal cutting. Why the hell did I buy a THC..., ooh, right. Because i needed one. Any thoughts or pointing me to some other post that addresses this issue.Thanks

tony3diWhat Peter is talking about is there is a file in Mach that has the configuration for Mach on you table, this is updated each time you make any changes. The file has the extension of XML and is kept in the XMLbackup folder under Mach 3. Look in the Mach main folder and fine the name of the XML file you changed (you can see 2 different names on my system in the attached image) your's may be plasma.XML (the date helps to see which on too). delete this file and go to the XMLbackup folder and find the last dated file (you may have many with the same date so look at the last time to). Copy that file and paste it in the main Mach3 folder. That should bring you back to the time before you made the changes.

xml file.jpg

xml file 2.jpg

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Thanks guys . You saved my bacon. I really would like to know what hapenned, but this interferences are starting to annoy the crap out of me. I'm almost ready to forget about THC . Since I have tryed to make it work I had nothing but problems. Would you guys like to share your best mach3 settings to Work with THC. Nevertheless i'm starting plans to add water bed to my table just in case.

well at least your hanging in there with it.If you have the signals hooked up correctly the only other things are the cut height (voltage for that) and speed for the metal thickness you are cutting. The THC should maintain cutting for the operation.

The X,Y stops moving when the Proma tells the Z to move, strange thing is that it was working pretty good. I think I may have lowered the debounce setting. I did raise it to 200 from 20 and will try it again. Sorry to hijack your thread like this, but alot of people have the Proma and seem to have issues but oddly there does not seem to be much on here about it.

No problem hijacking. The topic is the same. It hapenned to me when i raised the debounce # to high y and x axis would stop working. You must do some trial and error before you get the correct values for your system. I'm adding another ground rod below my plasma table, because most of my issues are noise related . For me Proma THC puts a lot of extra EMI trough the up /down/ arc /ground cable. And need to insulate that. Will be doing some test cuts later on and post results.

Yeah, I added a 6' ground rod under my table and have plasma work cramp on it and a heavy cable going to table. I have the ferrite chokes on all comm cables. I have all shielded cables grounded on the controller end. I was able to take my debounce setting from 20,000 down to 10. I think I may need to raise it up some.For some reason now when I try to use the Promo the torch stops moving after initiating the cut. I need to check my post processor and see if my defualt is the correct one.

Well..., having done alot of test cuts with proma, i now get the same result. when cutting with proma everything works great but suddenly Torch head stops moving on X and Y axis with flame still on and gcode still running. I went up to 10000 on 500 increments for debounce settings always with same result. enhanced pulse is on and 5us for motor pulse. Maybe my 5' rod is not getting good earth below floor. Any ideas on what else to try? I'm really frustrated right now.

You may have a problem with you BOB board or computer, since there is no feedback from the table to mach the code and keep running with nothing moving. The delay and ground rod only help it you are getting random noise and that will give you a reset condition and things should stop. Do you power both X and Y drivers from the same power supply? If for some reason the power supply shuts down Mach will not know that signals go out but nothing moves. Simple thing to check when this happens see if you can move the table in the X or Y directions by hand, if you can the motor have lost power.